I think the research into whether it has any effect scientifically is pretty limited tbh, considering the price I am dubious.
Whichever format you consume it in, your body will break it down the same way, which will be to break it down in the GI system as amino acids and distribute the small amount that remains of those as new peoteins which can be used in the body (along with whatever other rubbish is in there) across the global system. The collagen proteins created 'could' be converted to create new collagen or they could be converted to any other process on the body depending on it's needs (as determined by the body, not us). There is no data to suggest the former happens and it will depend presumably on each individuals system and needs.
It is not possible to 'take collagen' and it be directed towards any one thing in particular, such as skin.
I have a genetic condition that means I operate on reduced collagen, which causes problems such as joint dislocations, faulty arteries, fragile skin, prolapse organs (connective tissue needs collagen to support it). Every doctor I've seen has said no to collagen supplements as expensive and wasteful. This is before you consider the lack of regulation of the ingredients such as potential high levels of metals in marine collagen. Companies can day hat they like but there is little regulation at play as it's a food supplement, not a medicine.
You're just as well off cutting put any lifestyle habits that inhibit collagen production- sun, alcohol, smoking etc and ingesting foods that promote it, of which there ate plenty. Oral vitamin c is one, if you want a supplement.